<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>tansform实现居中</title>
    <style>

        .wrapper {
            width: 400px;
            height: 400px;
            background-color: #dddddd;
            display: flex;
            justify-content: center;
            align-items: center;
        }


        .box {
            width: 200px;
            height: 200px;
            background-color: #93d0ea;
        }

    </style>
</head>
<body>

  <div class="wrapper">
      <div class="box"> flex content</div>
  </div>


</body>
</html>